Patent attributes
A liquid pump for circulating working fluid (water) in a Rankine cycle comprises a U-shaped fluid vessel having a bending pipe portion and a pair of straight pipe portions, wherein a heating device and a cooling device are provided at one of the straight pipe portions for heating and cooling the water in the fluid vessel. The liquid pump further has a discharge pipe portion and an inlet pipe portion, and check valves are respectively provided in the discharge and inlet pipe portions. The water is vaporized by a heating operation of the heating device to increase pressure of the working fluid in the pump, so that the working fluid is discharged. The vaporized working fluid is then cooled down by the cooling device to decrease the pressure of the working fluid in the pump, so that the working fluid is sucked into the pump.